Brake shoe bonder



Oct. 20, 1953 J. c. HEINTLJR 2,655,974-

BRA'KE SHOE: BONDER Filed Nov. 23, 1949 5 Sheets-Sheet l Oct. 20, 1953 J. C. HEINTZ, JR

BRAKE SHOE BONDER Filed NOV. 23, 1949 3 Sheets-Sheet 2 JAMES c. HEINTz 11R.

ATTOR N EY Oct. 20,' 1953 J. c. HEIN-rz, .JR 2,655,974

v BRAKE SHOE BoNnER Filed Nov. 2s, 1949 s sheets-sheet s,

l x l l I I JAMES c. HEINTZ JR.

ATTOR N EY Patented Oct. 20, l1953 UNITED BRAKE slice nonnen J C Heintz. J r., Lakewood. Qhic Application Nevember 23. 1949, Serial NoV 129.118

(o1. s-s1).

1 5 Claims.

i This invention relatesv to brake shoe bonders for bonding friction-lining material to a brake shoe. More particularly, it relates to equipment for applying uniform and constant pressure be-7 tween a plurality of linings and their respective shoes, throughout the bondingoperation.

rIhe practice of applying a brake lining to a brake shoe by riveting the lining thereto has now been largely superseded by the recently developed method ofA adhesively bonding the lining material to the brake shoe. In this method the friction-lining material is positioned on the curved operating'surface of a h eated brake shoe with a layerof thermosetting adhesive interposed between them. The adhesive is usually applied in the form of a tape about sie inch thick. Heat sets the adhesive compound (by polymerization or otherwise). When heat is applied, the adhesive tends to liquefy before setting, and some is ab sorbed by the lining material and some may ooze out of the lamination. In any event, the thickness of the adhesive-bearing tape is reduced.

In the bender of this invention the pressure which forms the bond between the lining andthe shoe. is exerted by a fluidepressure cylinder and it remains. constant even though, during the bonding process, the thickness of the layer of adhesive is reduced. The. preferred bonderaccommodates a plurality of shoes and applies uniform and constant pressurel between each of the shoes and its. respective lining, through the bonding process. The pressure. member which contacts the linings is preferably exible, and the pressure is applied by fixing the two. ends of this member and moving into it the assemblies of the respective. brake shoes and. linings. TheV brake. shoes are supportedY on one. or more. mandrels, and heat for setting. the adhesive is supplied to the man.- drels during thepressing operation. As it is custernary, to. line brake` shoes in pairs, each device is advantageously designed to line twov brake shoes simultaneously.

A preferred bonder is constructedY of a frame which forms a vertical gudeway. Heaters located in the guideway are adapted to-- beV moved up. and down therein. The pressure cylinder, preferably operated.v pneumatically, is located` on the. frame-*adjacent to the guideway. The piston ofthe cylinder is connected to the. heaters through a first-.class lever or other suitable means, and. preferably also through pressureequalizins means. so that equal pressure. is applied to. each heater even though one may move moreA than the other in, formingv theA bonds be,-

thev respective, slices. and4 lining-s. The

Z brake shoes are held in mandrels. Mandrels of different sizes are provided to hold brake shoes of different sizes. The mandrels are removably positioned on the respective heaters and are heated by them, and move up and down in the guideway with them.

The flexible pressure member is advantageously a `steel strap provided with a loop at each end, with each end removably fastenable at different locations to permit the same strap to be used with mandrels and brake shoes of different radii.

The invention will be further described with reference to the drawings, in which is illustrated a preferred form of the invention.

Fig. 1 is a side elevation ofthe bender with the flexiblel pressure strap partially broken away to show the brake shoes and linings underneath it;

lig. 2l is a front elevation of the bender with the brake shoes and lin-ings positioned on a mandrel in press-ure contact with the flexible strap;

3Y is a View similar to. Fig. 2, but` showing the mandrels carrying the brake shoes and lining material out of contact with the flexible pressure member;

Fig'. 4i' is a top view of the` bender, with a portion of the pressure strap broken away;

Fig. 5 is a sectional View through the mandrels, etc., taken on they 5==5 of 4;-

Fig; 6. is a sectional view through the4 bendert on the line Gee-6. of Fig. l;V-

Eig. 7 is a top View of' the lever linkage taken on thel-ine ofA l;

Fig. 8` is a perspective view of a mandrel; and

Figc. 9; is a cross sectional, view through the mandrels, etc. quite similar tofF-ig. 5 with one of the mandrels raised: slightly higher than the other.

'he base of the brake shoeL bender consists of two. inverted channel sections l? and' 2-: which are welded' together to iorm a T; At the corners: of the channel 2, which is the. stem of the T, there areiupstanding angle iron supports 3f, whichA support the corners. of a plate A pneumatic cyl.- i-nder 5: is bolted. to. the top. of plate A and is poe sitionedfvlitlfrl its piston rod Ii (Eig. lf) projecting downwardly through. anl opening in the plate. Air may be admittedf to and exhausted from` the cylinder through suitable valve connectionsv and thepiping 8. An. air pressure gauge itisprovided. A cylinder actuated by water, oil, or any other luid, linden pressure, may be usedv instead of.` the preferred: pneumatic cylinder 5;

A side plate Il. is weldedv uprighton each. corner ofthe channel l. These plates arel parallel with. thel sides. of.' the channel.` I: and: ezt-tend` in from the ends of the channel I only a relatively short distance (Fig. 2). Along the innermost corner of each of these plates a right angle section is cut away so that the four plates II cooperate to form a vertical guideway I2 (Figs. 4 and 6). The heaters i3 and I4 are mounted for Vertical movement in this guideway.

The pivot I supported in lug i6 fastened to the base of the frame below the heaters supports the tines Il of a fork which form the shorter end of a lever arm. The longer portion I8 of this lever arm is pivotally fastened in the clevis I9 on the bottom of piston 1. The tines Il of the fork lie on opposite sides of the lower corner 20 0f the generally triangular or three-cornered plate 2| and are pivotally connected to this corner of the plate by the pin 22. The pin 22 ts loosely through a horizontal slot 23 in corner 20, and the ends of the pin are rigidly fastened to the tines I7 of the fork. The two upper corners 25 and 26 of plate 2| are pivotally fastened to lugs 21 which extend downwardly from the heaters I3 and I4. These connections permit a slight relative vertical movement between the two heaters which is advantageous when the lamination to be cured on one brake shoe is slightly thinner (or during Icure becomes slightly thinner) than the lamination on the other brake shoe. (See Fig. 9.) Ordinarily the heaters will be moved up and down in the guideway I2, side-by-side. The lever arm converts the downward force exerted by piston 'I into an upward force which lifts the heaters I3 and I4 in the guideway. The pivot I5 may be located at -any desired position intermediate the ends of the lever arm to compound the force of the cylinder any desirable amount.

The heaters I3 and I4 are best illustrated in the sectional View shown in Fig. 5. Each includes a box 28 in which is a resistance heating coil 29, and a cover 3B bolted to the box. Electrical cable 32 supplies power to each of the coils 29 and is connected with a suitable timing switch 34 which is mounted on plate 35 at the front of the apparatus. Warning light 3l is connected in the timing circuit to indicate when the bonding process is completed. A temperature gauge 39 is also provided on plate 35.

The pressure member 40 is a flexible non-elastic steel strap. A loop 4I is fastened to each end of the strap and these ends are held between the upright plates I I by pins 43 which extend through the loops and also through any set of the holes 44 in the plates II. A number of holes 44 are provided in each plate, so that the ends of the strap may be fastened at different positions and the same strap can be used with different sized brake shoes.

Each of the mandrels 48 rests on the top of one of the heaters I3 and I4. The mandrels are made of a heat conducting material so that they eciently transfer heat from the heaters to the brake shoes. One of the mandrels is illustrated in Fig. 8. One side of each mandrel (the back side in Fig. 8) is flat and when a pair of the mandrels is in the guideway these sides are in contact with one another. The side 50 is provided with stepped portions 5I at each end which lit inside the plates II. The upper surface 53 of the mandrel is convex to conform to the concave curvature of the flange 54 of the brake shoe and this upper surface is grooved Iat 55 to receive the web 56 of the brake shoe. A number of pairs of mandrels may be provided for each bonder to handle brake shoes of different sizes. The different mandrels will each be provided with identical stepped portions 5I so that they will each fit the guideway I2.

Mandrels of other design may be used so long as they may be fitted into the guideway of the device. It will be particularly advantageous to use the improved mandrel described and illustrated in my co-pending application Serial Number 129,119, led November 23, 1949. This mandrel is formed in two sections between which the web of the brake shoe is held. The sections are both heated and each is pressed tightly against the web by spring means, so that the iiange of the brake shoe is heated uniformly.

To bond lining 59- to a brake shoe, the convex outer surface of the flange 54 is thoroughly cleaned from rust and whatever residue there may be from the old lining. A thermosetting adhesive 62, preferably in the form of a tape, is then applied to the cleaned surface. Any adhesive may be used which on heating is capable of uniting the lining 59 to the flange 54. The lining 59 is placed over the adhesive and then the brake shoe is positioned on the proper sized mandrel. The mandrels need not be removed from the device after a cure is made so that usually the mandrels will be already in the guideway and the shoes together with the laminations will be simply slipped on to the mandrels.

The ends of the strap 45 are held by the pins 43 in those holes 44 which will best accommodate the particular mandrels employed. The position of the apparatus after it has been assembled and before pressure is applied is shown in Fig. 3. Air under pressure is introduced into the pneumatic cylinder 5 and the timing switch 34 is started. This forces piston 'I downward thereby raising the heaters i3 and I4 carrying the mandrels and the brake shoes, and presses the lamination tightly against the strap 4I). As the heat softens the adhesive it impregnates the lining and, although this will reduce the thickness of the lamination, the pressure remains constant. When the adhesive has been set the air pressure is turned off manually or automatic-ally, and the weight of the heater and mandrel cause the short end of the lever arm to resume the position shown in Fig. 1.

The lining 59 is a tough, pressed ber composition formed in strips which are usually from about 1A; to 1%,- inch thick. One of the lining strips may be slightly thicker than another, and there may be a similar variation in the relative thicknesses of the adhesive strips. Also the flanges of the brake shoes may be of different thickness. Therefore the total thickness of the flange and the lamination of one of the brake shoes may diiTer from that of the other shoefor example, as much as als inch. The pressure of the two shoes and laminations against the strap 48 is equalized by the three-cornered plate ZI which permits relative vertical movement between the two heaters.

Fig. 9 shows two brake shoes 'i0 and 'II positioned on mandrels 43 in the bonder with the lamination of each shoe in pressure contact with strap 40. The flange and lamination of brake shoe 'I0 are shown thicker than the iiange and lamination of shoe 1I. When pressure is applied with these brake shoes positioned on the mandrels, the lever arm lifts the heaters and mandrels side-by-side until the lining of brake shoe 'l0 is in pressure contact with the strap. The upward movement of this brake shoe will then stop. The continued upward force exerted by the lever arm then rotates the three-cornered lplatel 2l slightly about the pivotal connection at corner 25 causing the mandrel carrying shoe 'H to move upward relatively to the other mandrel until both brake shoes arein pressure contact with the strap v'and the linings and adhesives are under equal pressure. The slotted connection of lower corner '2G and the 'clearances at the other pivotal connections will permit this slight rotation of the plate 2l about either of its corners 25 or 26. Y

Adhesives which set by polymerizing and adhesives which set by other chemical interaction (e. g., adhesives of the phenol-aldehyde type, etc.) may be used. The temperatures and times of heating krequired for the different adhesives are known in the art. Y i

The mandrel, and even the brake shoes, may be preheated vto speed the operation of the bonder.

The invention is described herein with reference to an internal expanding type brake shoe having an arcuatelyl curved, flat flange with'lan arcuate thin web projecting 'from the concave side of the flange." This type shoe is T-shaped in transverse cross section and is commonly used in brakes for motor vehicles. It is recognized that this brake shoe bonder may be adapted for other types of brake shoes or members carrying such a friction lining facing. For example, mandrels may be 'provided to'accommodate shoes having two projecting webs, and-other mandrels may be provided together vwith, suitable pressure members toaccommodate brake shoes of different curvatures. If desiredthe device may be easily designed with only one heater adaptedto carry 4one or more mandrels. .Ylt is recognized that the heating unit may be slightly convex and the under-surface of the mandrels correspondingly concave to make more uniform the depth of the mandrel through which the heat must be transferred from the heater. 'Other modifications may be made inf-the vequipment and process without departing from'the invention which is defined in the appended claims.

WhatIclaim is:

l. A brake-shoe bonder for bonding friction lining material to a brake shoe which comprises a pressure member adapted to t against the lining, a heat-conductive outwardly curved, elongated mandrel with a longitudinal groove therein for supporting the brake shoe and a guideway therefor, a pressure cylinder equipped with a piston, means to transmit force exerted by the piston to the mandrel and means for heating the mandrel.

2. A brake-shoe bonder for bonding friction lining material to a brake shoe which includes a Y guideway, a heater slidably mounted in theA guideway, adjacent the heater a removable mandrel with a curved slit surface to hold at least one brake shoe, a pressure member, and yieldable means for exerting pressure against the heater to press the mandrel and brake shoe toward the pressure member.

3. A brake-shoe bonder for bonding friction lining material to a brake shoe which includes a vertical guideway, a heater adapted to slide up and down in the guideway, removably mounted on the heater a heat-conducting mandrel adapted to hold a curved brake shoe having fresh lining material thereon, a pressure member over the lining material, and yieldable means for exerting upward pressure on the heater to press the lining material against'the pressure member.

4. A brake-shoe bonder for bonding friction lining material 'to' a brake sho'e which. includes a vertical guideway,.a heater adapted toslide' up and down in the 'guideway, removably mounted on the heater a heat-conducting mandrel adapted to hold a curved brake shoelhaving fresh 1in'- ing material thereon, a flexible steel 'strap' removably located over the lining material, and means for exerting upward pressure on the heater to press the lining'material against the Strap. Y n Y Y 5. A brake-shoe bonder for bonding friction lin"- ing material to a brake shoewhich includes a vertical guideway, a heater adapted to slide iup and down in the'guideway, removably mounted on the heater a heat-conducting mandrel adapted to hold Va curved brake shoe havingfre'sh lining material thereon,a pressure member'over the lining material Whichlconformsto the4 c'ur- Vature of thebrake shoe, a pressure cylinder equipped with a piston, and means connecting the piston andh'eate'r to move the heater upward to press the lining material against the pressure member. Y Y, .Y .Y Y.

6. A brake-shoebonder for bonding liningmaterial to a brake shoe which' comprises a guide'- way, across the guideway a flexible pressure member at least one end of Which is removably fastened to the'bonder, movably positioned in the guideway, a support adapted to hold a brake shoe with lining material thereon, and'yieldable means for moving the "support in the guideway toward the flexible member. f Y

'7. A brake-shoe bonder for bonding lining mel- "terial to a brake shoe,"which comprises 'ae'xible pressure member the ends'of which are fastened by removable'means,adapted to be 1ocatedv at different positionsfin the bonder vto give a desired curvature tothe pressure l-r'ne'ml'aen-"an outwardly rvcurved,`felongated mandrel with'Av a longitudinal' groove'thereinfadapted to hold va brake shoe with lining material thereon,- means forheatin'glthe mandrel, a lguideway therefor and yieldabl'emeans for pressing the mandrel toward the flexible-member. "i

8. A brake-shoe bonder for bonding friction lining material to a brake shoe which includes a flexible pressure member, a plurality of means positioned side-by-side, each for supporting a brake sh-oe having adhesive and lining material thereon, means for exerting pressure on the plurality of supporting means to press them toward the flexible member, and pressure-equalizing means between the pressure-exerting means and the several supporting means whereby the pressure is distributed uniformly so that each supporting means exerts the same pressure toward the flexible member regardless of the distances the respective supporting means are moved toward the flexible member.

9. A brake-shoe bonder for bonding friction lining material to a brake shoe which comprises grooved, outwardly curved, elongated mandrels for supporting a plurality of brake shoes with adhesive and lining on each, a pressure member,

means for pressing said mandrels toward the pressure member so as to thereby press the linings and -shoes toward one another and pressure-equalizing means for applying the same pressure to each of the shoes and its respective lining.

l0. A brake-shoe bonder for bonding friction lining material to a brake shoe which comprises grooved, outwardly curved, elongated mandrels for supporting a plurality of brake shoes withv adhesive and lining on each, a pressure member,

meinem '-ineansz for' pressing saidi mandrels tomar 'the pressure member se as to thereby press: timelin- .anxi shoes. toward: yone. another, andipresr Sme-equalzing means #between the. pressingmeans-and the pressure. member .for applying the -SaamefpJ-esslme teaeh of the shoes amr its're.- xspecthieflining.

i Y 11,n A brake-shoe bonner for bonding Ming-'material t0, a. brake vshoe which includes. ya guideway, two heaters movably positioned side- 11E-side in; the; guidewasr, each heater being adapted. to sunplyf heat; to. a.. brake-shoe support during'itlie anplicatien for a lining. thereto., mean-s enexertin'g: pressure :against the heaters. to. more them; in the guidewaaz, and pressuref-equalizm'g means; connecting) the respective heaters with the pressure.- exertingy meanswhereby the heaters :memorable relatiren'r to one. another.

,A braheshoe bender 12er.bendingY friction :lining material to a, brake shoe which includes a. vertical lesuidetvay, two. heaters `-positioned sidefbr-side the feu-influer movablev vertically therein, lining-contacting means across the gauidewaih pressure-.exerting means; adapted t0 more the heaters. toward the lining-.contacting means.x and` means conmeting therespeetive heaters with the,A pressureeexertine means. wherethe .lieateifiy are4 'immovable relativelyl :to vone :another.

:i3--A brakefshoe.y bender for bonding .friction lining materialtefawbrake shoe which includes a. vertical guideway, two heaters. DQSitionedv side.- hyside in the fguideway and movable, vertically therein,t linings-contacting" means across the pressures-exerting means adapted `to move the. heaters toward 'the -liningfcontacting means. and.: a threeecornerefi plate two.. cor- :nersl et which are-.pivotally fastened'. to. the re- :spet'ive .heaters and. third. corner fof which is pivotant?l fasteneii to; the .pressure-.exerting means. l

14. .A brakeshoe benderv ier bending material la. brake a vertical guideway.. a heater slidably mounted in the :guidi-Maly.. 'adja- :'cent.. theheater amandrell with a., curved slit subface, to hold at least. onewbralie shoe, Va exible -pressure member., and yieidalsa-le means `for exert- Yconsta:ntrpessureagainst theheater to press the mandrel. and brake shoe toward. the pressure member.

i5; A brake-shoel bunder for bonding friction lining.v material ltel va pluralityV of brakev shoes which. includes` a pressure .member adapted to apply pressure to lining materials conformed to the shape- 0f the brake shoes, a .plurality of groeved, outwardly curiced.. elongated; mandrels positionea sideabysside, each ier supportinga brake; shoe.- having adhesive and lining material thereon, a. silpport Afor each mandre1, pressure.- equalizing means attached tothefsevleral'supports WlalerebyI pressure va-npliecltherete is. distributed uniformly that the same pressure, is lsnpplieci to each support regardless of the distance leaeh .support :moves when pressure is. applied., .and `means fer pressing, :saidy pressure meinberand thel 'pressure-equalizina meansagainst brake -fs-hoes Supported by said mandrels.

JAMES: C. HENTZ., Jfii.

References .Cited in the le ef this patent STATES PATENTS Grizzley: Saftibond Brake Lining-'Bonding Equipment, Grzzley Manuacturing- Co., Paulding, Ohio, Brinted'uly- 19.49. 

